export type PromiseType<T> = T extends Promise<infer U> ? U : T;
export type AsyncReturnType<F extends () => any> = PromiseType<ReturnType<F>>;
export declare abstract class ExtensiblePromise<T> implements PromiseLike<T> {
    constructor();
    readonly promise: Promise<T>;
    protected _resolve: (arg: T) => void;
    protected _reject: (reason?: any) => void;
    then<TResult1 = T, TResult2 = never>(onfulfilled?: (value: T) => TResult1 | PromiseLike<TResult1>, onrejected?: (reason: any) => TResult2 | PromiseLike<TResult2>): Promise<TResult1 | TResult2>;
    catch<TResult = never>(onrejected?: ((reason: any) => TResult | PromiseLike<TResult>) | undefined | null): Promise<T | TResult>;
}
/**
 * A Promise-Like class that can be controlled (resolved/rejected) via a public API
 */
export declare class ControlledPromise<T> extends ExtensiblePromise<T> {
    resolve(p?: T): void;
    reject(e?: any): void;
}
export declare const delay: (ms: any) => Promise<unknown>;